Vertically and Crosswise Multiplication

This is an extremely useful method for high school students while learning multiplication of larger numbers. A lot of time is spent on performing multiplication operations and multiplication is an integral concept in Mathematics. Using this method, multiplication of larger numbers can be performed in a single line. It can done as follows:

  1. For two digit numbers, follow an ‘X’ shape. We can proceed from either left to right or right to left. Here, let us see from right to left. Consider 63 * 83. It can be done as follows:

ð  3 * 3 = 9.

ð  (6*3) + (8*3) = 42.

ð  6 * 8 = 48.

ð  It becomes 48 42 9 =  5229

  1. For three digit numbers, eg, 421 * 123, proceed as follows:

ð  3 * 1 = 3

ð  (3*2) + (2*1) = 8

ð  (3*4) + (1*1) + (2*2) = 17

ð  (4*2) + (2*1) = 10

ð  4 * 1 = 4

ð  It becomes 4 10 17 8 3 = 4 117 8 3 = 51783

  1. For four digit numbers, eg, 1234 * 5631, proceed as follows:

ð  4 * 1 = 4

ð  (3*1) + (4*3) = 15

ð  (2*1) + (3*3) + (4*6) = 35

ð  (1*1) + (2*3) + (3*6) + (4*5) = 45

ð  (1*3) + (2*6) + (3*5) = 30

ð  (1*6) + (2*5) = 16

ð  1 * 5 = 5

ð  It becomes 5 16 30 45 35 15 4 = 5 16 30 45 3654 = 5 16 30 48654 = 5  16 348654 = 5 1948654 = 6948654.

Huge multiplications in a single line. Now that’s simple, isn’t it? 🙂

P S It’s also my favorite. This was what got me hooked !

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One thought on “Vertically and Crosswise Multiplication

  1. This is very cool. However, I think this could be better explained with diagrams. What say we draw some up and make an improved version of this post?

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